Adjustable support for school furniture



v (No Model.)

A ANDREN ADJUSTABLE SUPPORT FOR SCHOOL FURNITURE. N0. 540,531.

Patented June 4, 1895.

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i===nllllllllllll "UN-men STATES PATENT 'rr cni. I

ALBAN ANDREN, OF BEVERLY, ASSIGNOR TO THE CHANDLER ADJUSTABLE CHAIR AN-DDESK COMPANY, OF BOSTON, MASSACHUSETTS.

ADJUSTABLE SUPPORT FOR SCHOOL FURNITURE.

SPECIFICATION forming part of Letters Patent No. 540,531, dated June 4,1895.

Application filed February 11,1895. Serial No. 537,887. (No model.)

To an whom itmay concern:

1% it known that I, ALBAN ANDRFN, a citizen of the United States, and aresident of Beverly, in the county of Essex and State of 5Massachusetts, have invented new and useful Improvements in AdjustableSupports for School Furniture, of which the following, taken inconnection with the accompanying drawings, is-a specification.

This invention relates to improvements in adjustable supports forfurniture such as desks, chairs, seats, 650., and it is particularlywell adapted for school furniture which requires adjustment'from time totime relative r 5 to the height or size of the scholar for which thechair, seat or desk, &c., is to be used. Ad-

j ustable supports for this purpose are principally of two kinds,namely, those depending on interlocking pawls, teeth or corrugations, 2cand those in which the parts are held together by frictional contact.

My invention relates to the latter kind. In frictional holding andadjusting devices for thispurpose it is of the greatest importance 2 5that the friction holding device should be so perfect and positiveas toprevent the parts from moving relative to each other after beingadjusted and clamped together and for this purpose I construct myinvention as follows, reference being had to the accompanying drawings,wherein-'- Figure 1 represents a side elevation of my improved adjustable device, shown as applied to a chairor seat. Fig. 2 represents arear 3 view. Fig. 3 represents a central vertical section. Fig. 4:represents a cross-section on the line 4 4:, shown in Fig. 3; and Figs.5 and 6 represent modifications of such cross-section.

Similar letters refer to similar parts wher- 0 ever they occur on thedifferent parts of the drawings.

A represents the flange of the upwardly projecting base portion A whichis preferably made of semi-circular or curved section as shown in Fig.4, or it may be made of a V shaped or l l shaped section or flat orequivalent cross sections as shown respectively in Figs. 5 and 6 withoutdeparting from the essence of my invention. The interior portion orsurface aof the upright base portion A is wedge shaped or inclined asshown in Fig. 3.

B is the vertically adjustable shank secured at its upper end to thefurniture 0 in any suitable manner, which shank has a crosssectioncorresponding to the interiorshape of the upright base portion A asshown in the drawings. I

The shank B has a wedge shaped or inclined front surfaceB' adapted tofit against the inclined or wedge shaped interior surface a. of theupright base portion A as shown. The rear portion B of the seat orfurniture shank B is also made inclined or wedge shaped, and against itis fitted a clamping wedge or inclined bar D the lower end d of which ispreferably pivoted or made to rest .in, a cavity a in the base portionas shown in Fig. 3.

b is a vertical slot in the seat or furniture shank B as shown.

E is a headed screw threaded fastening bolt passing through a notch orperforation in the upright base portion A and through the slot 1) in theseat or furniture shankB, as well as through a perforation in theclamping wedge D and provided with a nut e or other suitable fasteningdevice as shown.

The clamping wedge D has an inclined surface d adapted to fit againstthe inclined or Wedge shaped rear portion B of the furni 8o ture shank Bas shown.

From the above it will be seen that four inclined or wedge shapedfrictional surfaces are employed in my improved device, namely, theinterior wedge shaped or inclined surface a of the upright base portionA, the front inclined or wedge shaped surface B of the shank B, the rearinclined or wedge shaped surface 13 of said shank, and the interiorinclined or wedge shaped surface (1 of the 0 clamping wedge D as fullyshown in Fig. 3.

It will thus be seen that I do not depend on simply two inclined facesto secure the 'furni ture shank to the base portion, but depend on twicethe number, or four, inclined or 5 wedge shaped surfaces to effect theresult of positively securing the furniture shank to the upright of thebase portion by which I am enabled to secure the parts together withoutdanger of sagging when a downward pressure ion is brought to bear on theseat or other furniture. In this manner I obtain a most strong andpositive frictional holding device which is capable of a most nicevertical adjustment to any desired height without the need of cogs,grooved bars, pawls or other interlocking devices.

Having thus fully described the nature, construction, and operation ofmy invention, I wish to secure by Letters Patent and clai1n 1. Anadjustable support forschool or other furniture consisting of a baseportion having an interior inclined or wedge shaped surface, avertically slotted and vertically adjustable furniture shank having onone side an inclined or wedge shaped surface adapted to fit the saidinterior inclined surface of the base portion and provided on itsopposite side with a similar inclined or wedge shaped surface, a movableouter wedge or clamping bar having an inclined or wedge shaped surfaceadapted to fit against the adjacent inclined surface of the shankopposite the point where said shank bears against the base, and a screwbolt passed through said wedge and base and through the vertical slot ofthe intermediate furniture shank and provided on one end with a head andon the other end with a nut, substantially as and for the purpose setforth.

2. An ad justable support for school orother furniture, consisting of abase portion having an interior inclined or wedge shaped surface, avertically adjustable furniture shank provided with a verticallyelongated slot, the opposite sides of said shank being formed withinclined or wedge shaped surfaces one of which is adapted tofit againstthe said interior inclined surface of the base portion, a movable outerwedge or clamping bar having its lower end pivotally supported on oneside of the base portion and the inner surface of said wedge or barbeing inclined or Wedge shaped to fit against the adjacent inclinedsurface of the furniture shank, and a headed screw bolt passed throughsaid movable wedge and through the base portion and the vertical slot ofthe furniture shank and provided with a nut, substantially as shown anddescribed.

In testimony whereof I have signed my name to this specification, in thepresence of two subscribing witnesses, on this 6th day of February, A.I). 1895.

ALBAN ANDREN.

Witnesses:

VVINTHROI L. MALooN, IIOL'IEN B. PERKINS.

